It is known to transport articles, in particular baggage, on conveyor systems in which the articles are situated in trays, boxes or totes, in order to treat the articles more careful and prevent damages on and wear of the articles and interruption of the operation of to the conveyor system caused by pendent parts of the articles, such as belts. The totes may be separated from the conveyor line, cf. EP-A-0 456 297, EP-A-0 742 163 and U.S. Pat. No. 5,301,790, to store the articles temporarily together with the tote.
The totes generally consist of two parts, a first part that supports the article to be transported, such as a tray having a concave surface as shown e.g. in U.S. Pat. No. 5,301,790, which prevents the article from sliding off the tote and facilitates the discharge of the article by tilting of the tray, and a second part to support the first part as well as transferring the driving force from the conveyor line to it and thereby to the article. Thus, the second part is exposed to heavy wear from the contact with the drive means of the conveyor and should therefore be manufactured from a wear-resistant material. For one of the known types, the second part is designed to engage dedicated conveyor and drive means and the wear-resistant material may be a glass-fibre reinforced plastics material, as disclosed in EP-A-0 581 398, or may be metal as disclosed in WO 01/05685. Another known type is the rotationally moulded tote having a hollow interior and a flat lower surface that support the tote on tilt trays, such as disclosed in U.S. Pat. No. 5,301,790, on belt drives, chutes, etc. The wear-resistance of materials that are suitable for rotational moulding is low but in so far as the totes are used solely on tilt trays, the wear-resistance properties of the rotationally moulded tote may suffice. The shape is advantageous because the totes may be transported on a multitude of different types of conveyors, but for use at conveyors with belt drives etc. in which the totes are driven directly, the wear-resistance of the material is insufficient and the lower surface of the rotationally moulded tote has to be reinforced by a sheet of a wear-resistant material, typically a steel sheet.
It is furthermore a known demand to conveyor systems that the articles transported thereon may be subjected to x-ray analysis, e.g. for quality inspection in production lines, but more commonly for security control of baggage for content of explosives, etc. To ensure the quality of the x-ray inspection which is performed with a vertical ray direction, it is required that material situated between the x-ray source and the x-ray detector is fairly transparent to x-rays and that the damping of the intersecting x-rays is substantially uniform throughout the inspected area perpendicular to the ray direction. As the known totes does not fulfil these requirements, mainly due to the presence of metal sheets or glass fibres, which both prevent the use of x-rays, the articles may in known systems be x-rayed before they are loaded onto the totes, the articles may be unloaded from the totes before the x-ray analysis and subsequently re-loaded onto the totes, or the totes may be separated in the first part carrying the article and the second metal part prior to the x-ray analysis, followed by a reunion of the two parts afterwards as disclosed in WO 01/05685. The tote manufactured by rotational moulding is in itself suitable for carrying articles for x-ray analysis but the material used for reinforcement of the lower surface severely reduces the x-ray transparency of the tote thus renders the tote unsuited for carrying articles during x-ray analysis thereof.